body{
    height: 100vh;
    background-color: gray;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-flow: column;
}
#box1{
    width: 300px;
    height: 300px;
    background-color: black;
    color: yellow;
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
}
button{
    margin-top: 20px;
    background-color: skyblue;
    padding: 10px;
    width: 100px;
    border-radius: 3px;
    border: none;
    font-family: '华文行楷';
    transition: all 0.2s linear;
}
button:hover{
    background-color: blue;
    color: white;
    transform: scale(1.05);
}